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    <!-- 宝石与石头 -->
    <script>
      var numJewelsInStones = function (J, S) {
        J = J.split('')
        let index = 0
        for (let s of S) {
          if (J.includes(s)) index++
        }
        return index
      }
      console.log(numJewelsInStones('aA', 'aAAbbbb'))
    </script>
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